Calcium Ionophore A23187 treatment to rescue unfertilized oocytes: a prospective randomized analysis of sibling oocytes

Marga Esbert, Andrew Carmody,
Reproductive BioMedicine Online. Available online 28 June 2022. 2022 doi:


RESEARCH QUESTION: Can 1-day old human unfertilized oocytes activate and blastulate after the exposure to Ca.I A23187? DESIGN: Prospective randomized trial analysis of sibling oocytes. Seventy unfertilized sibling oocytes from 24 couples were randomly split into two groups. In the treatment group, 35 oocytes were cultured with 5μM Ca.I A23187 for 10 mins, washed and cultured until day 6 of development (D+6). The remaining 35 oocytes (control group) were similarly cultured until D+6. Activation, cleavage and blastulation rates were compared between the two groups. RESULTS: Comparable activation rates were observed in the oocytes incubated with Ca.I A23187 and in the control group (11.4% vs. 17.1%; p=0.49 ). The cleavage rate observed was 45.71% in both groups. None of the embryos reached the blastocyst stage. CONCLUSIONS: Activation and cleavage can occur in unfertilized oocytes following the diagnosis of failure to fertilize. Unfortunately, the prevalence of activation is not impacted by exposure to Ca.I A23187. Additionally, these embryos have no tangible reproductive potential as they arrest prior to reaching the blastocyst stage.